Does anyone know of a friction hitch that can be used to descend a double rope? I'm not refering to a Blake's hitch (or the equivalent) used in DdRT, but a hitch that can be tied around both strands of, say, a half inch climbing line and then used to descend with.
Friction hitch on double rope
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Kneejerk Bombas
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For footlocking a doubled rope, guys use a prussic, but more for locking off if you fall. With all your weight on a single rope (or single set of ropes) a friction hitch will lock off like mad. If you do get it to slide, the friction will be very hard on the rope (can you say burn) as well as very hard to smoothly control.
A standard climbing system gives you a 2 to 1 advantage, which takes at least half the load off your hitch, and even more than half if you have friction at the TIP (like with a natural crotch).
A standard climbing system gives you a 2 to 1 advantage, which takes at least half the load off your hitch, and even more than half if you have friction at the TIP (like with a natural crotch).
squisher
ArboristSite Operative
what sort of application were you thinking of that for or were you just wondering if it's possible? Standard I think would be to use a descending device like a figure eight and back it up with a prussic.
Basically, is there a knot equivalent of a figure 8. Ekka showed how he has his climbers set up a false crotch with a figure 8 so if the guys hit a bees nest or something while they're on spikes up in the tree, they can descend quickly on the 8. (He called it absail or something like that.)
I was just wondering if there's a knot that can do the same. Maybe a Klemheist might work?
I was just wondering if there's a knot that can do the same. Maybe a Klemheist might work?
Tom Dunlap
Addicted to ArboristSite
Any of the usual friction hitches will work. You'll have to take the time to test the many combinations to see how each works though. If you used a doulbed half inch rope you should start experimenting with the same rope tied using a friction hitch.
But...why???
You can abseil, rap, rappel, descend... using a Munter on a large diameter HMS biner.
But...why???
You can abseil, rap, rappel, descend... using a Munter on a large diameter HMS biner.
I tried a Klemheist hitch today and it worked great. The cord got pretty hot, but my descent was very controllable. Next up is trying a Munter on a carabiner. It's more for just seeing what different things work. The Munter is on my list of things to practice with for sure.
Thanks to all.
Thanks to all.
Tree Machine
Addicted to ArboristSite
I would recommend looking places other than a friction hitch. Having tried that, and having used mechanical pieces like an ATC or similar tube device, or even the big ring from a friction saver, there are many easy-to-learn and inexpensive ways to descend down a static doubled line.
A Munter will work, but it'll twist your rope. Works OK with SRT, but static doubled rope and 13mm line, you'll wanbt a fairly big biner, or a locking scaffold hook (a really big caribiner). A figure 8 also has the problem of twisting your rope.
With most belay devices, the predominant friction control comes from the passing of the rope through the piece. The remainder comes from your hand. Whereas with a friction hitch, you let go to stay suspended. With most devices you set up a soft lock, or a hard lock to stay suspended; a secondary point of friction equal to or greater than what your belay hand was providing.
Spare yourself the agony and skip the Prussik altogether. Mike says
A Munter will work, but it'll twist your rope. Works OK with SRT, but static doubled rope and 13mm line, you'll wanbt a fairly big biner, or a locking scaffold hook (a really big caribiner). A figure 8 also has the problem of twisting your rope.
With most belay devices, the predominant friction control comes from the passing of the rope through the piece. The remainder comes from your hand. Whereas with a friction hitch, you let go to stay suspended. With most devices you set up a soft lock, or a hard lock to stay suspended; a secondary point of friction equal to or greater than what your belay hand was providing.
Spare yourself the agony and skip the Prussik altogether. Mike says
I've seen this in footlocking competitions, but nowhere else. If they're using it in the field they're stuck in time and need to move on to something that allows smoother, fully controllable friction. There are literally hundreds of better options.Mike Maas said:
PUclimber
ArboristSite Operative
Prussic or kleimhiest backed up with figure 8
The prussic locks up so bad due to the friction that is placed on it. By running a second point of friction such as a figure 8 below it takes some of the friction off it and is able to slide. Also you work the tree off the double rope? Most just use this as a way of accessing the canopy.
The prussic locks up so bad due to the friction that is placed on it. By running a second point of friction such as a figure 8 below it takes some of the friction off it and is able to slide. Also you work the tree off the double rope? Most just use this as a way of accessing the canopy.
PU Cllimber's strategy works if line between hitch and device is kept tight i think. Hitch around both legs of line at once limits how close you can safely get to support / TIP by ~5x the horisontal diameter of the support; or the tension of the spread on the lines can pull hitch open.
The mechanics of load friction on a hitch descending while grabbing all support legs is different than that of a friction hitch grabbing 1 of 2 legs of support.
Most obvious is that all your weight instead of at most half is on the sliding friction of the hitch; then less than that for the participle of friction at support. But the real kicker i believe, is that if you have 2 legs of support and are riding a friction hitch down on one leg; the other leg automatically takes your weight. i think this is analogous to if the friction hitch leg of support was stretching or failing, the other leg automatically takes the loading. So in DdRT the sliding friction hitch might unload to 20# or less. That is lots less friction descending in this DdRT example than in SRT or your pro-posed DRT(?) with a friction hitch. IMLHO; after lots of experimentation; descending on a friction hitch not in DdRT is beyond the design scope and safety of a friction hitch.
Fig. 8's and Muenters with gloved back up hand can work; the metal device not wearing the same as a hitch and acting as a heat (draining) sink too. Aluminum dissipating heat faster than steel, but then too you can get burnt easier on the non-friction side of device then too. Spiraling can be a problem. It is best if the line is completely free of spirals to start; line barely reaches ground so it can let spirals venture off/ not be trapped by weight of line after hitting ground. And also if the line on the Bitters side of device is held to be inline with/ not bent perpendicular to the line on the Standing Part side of device. Muenter is typically harder on line by the sharper bend and rope grinding against self when moving.
The mechanics of load friction on a hitch descending while grabbing all support legs is different than that of a friction hitch grabbing 1 of 2 legs of support.
Most obvious is that all your weight instead of at most half is on the sliding friction of the hitch; then less than that for the participle of friction at support. But the real kicker i believe, is that if you have 2 legs of support and are riding a friction hitch down on one leg; the other leg automatically takes your weight. i think this is analogous to if the friction hitch leg of support was stretching or failing, the other leg automatically takes the loading. So in DdRT the sliding friction hitch might unload to 20# or less. That is lots less friction descending in this DdRT example than in SRT or your pro-posed DRT(?) with a friction hitch. IMLHO; after lots of experimentation; descending on a friction hitch not in DdRT is beyond the design scope and safety of a friction hitch.
Fig. 8's and Muenters with gloved back up hand can work; the metal device not wearing the same as a hitch and acting as a heat (draining) sink too. Aluminum dissipating heat faster than steel, but then too you can get burnt easier on the non-friction side of device then too. Spiraling can be a problem. It is best if the line is completely free of spirals to start; line barely reaches ground so it can let spirals venture off/ not be trapped by weight of line after hitting ground. And also if the line on the Bitters side of device is held to be inline with/ not bent perpendicular to the line on the Standing Part side of device. Muenter is typically harder on line by the sharper bend and rope grinding against self when moving.
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Tree Machine
Addicted to ArboristSite
From Mihalek's question what I hear is that he's found that ascending 1:1 on a doubled line is more efficient; about twice as fast and easier because you have half the number of footlocks as with a traditional 2:1 system to get up there, and many find footlocking two lines with your feet easier than footlocking a single line. He's found the advantage there pretty obvious. This is DdRT vs DbRT.
Once up in the tree, you flipline in and pull the end of your rope up and fashion a traditional friction hitch which, depending on how high up you are can cost you quite a bit of time in getting the rope up there and configuring your hitch.
The question (in my own words) asks, is there a way to safely attach to the doubled line as it stands in front of you and move on to treecare working off these parallel lines.
The answer is a definite yes. The method works identically to SRT; you just treat the two lines as if they were one. Both ends are on the ground and both lines are not moving, relative to the tie-in point. It is a 1:1 abseil where 100% of your friction is created and controlled in front of you and eliminates the need for a friction saver as there is only the weight of you, your gear and your rope on the crotch. The rope presses down on the tree, but does not slide over the area.
There's a number of advantages in speed, efficiency, minimizing gear and lessened rope wear in approaching ascent / descent in this manner. Ya just gotta figure out how to do it.
Since the thread is about using a friction hitch on this 1:1 system, I'll step out. I might use a friction hitch to back up the friction controller, but I wouldn't use the friction hitch AS the friction controller. This doesn't mean it's not possible, but the alternatives to a friction hitch are easy and inexpensive. The hardest part is the shift in mindset.
Once up in the tree, you flipline in and pull the end of your rope up and fashion a traditional friction hitch which, depending on how high up you are can cost you quite a bit of time in getting the rope up there and configuring your hitch.
The question (in my own words) asks, is there a way to safely attach to the doubled line as it stands in front of you and move on to treecare working off these parallel lines.
The answer is a definite yes. The method works identically to SRT; you just treat the two lines as if they were one. Both ends are on the ground and both lines are not moving, relative to the tie-in point. It is a 1:1 abseil where 100% of your friction is created and controlled in front of you and eliminates the need for a friction saver as there is only the weight of you, your gear and your rope on the crotch. The rope presses down on the tree, but does not slide over the area.
There's a number of advantages in speed, efficiency, minimizing gear and lessened rope wear in approaching ascent / descent in this manner. Ya just gotta figure out how to do it.
Since the thread is about using a friction hitch on this 1:1 system, I'll step out. I might use a friction hitch to back up the friction controller, but I wouldn't use the friction hitch AS the friction controller. This doesn't mean it's not possible, but the alternatives to a friction hitch are easy and inexpensive. The hardest part is the shift in mindset.
I learned pretty quickly from watching Moss demonstrate SRT at the inaugural Boston Tree climb how efficient the 1:1 ascending systems are. I'm still in the DdRT mode, but may switch to SRT for getting into the canopy and then switch to DdRT for moving around once aloft.
This issue of descending on a doubled rope came up when I saw Ekka's video of how they set up a false crotch when doing takedowns (on spikes) so that if a hazard is encountered, the climber can get down fast on the rope with an 8 versus having to spike down. I was wondering if such an emergency descent could be done without a Figure 8 by using some kind of knot combination.
As I mentioned, I tried a Klemheist hitch on a doubled rope and it worked pretty well for a short descent. I stopped descending when I let go and was able to start descending again by applying pressure to the top wrap of the hitch. I'll need to try it on a longer descent to see if it continues to perform well. The cord got pretty hot on the short descent.
This issue of descending on a doubled rope came up when I saw Ekka's video of how they set up a false crotch when doing takedowns (on spikes) so that if a hazard is encountered, the climber can get down fast on the rope with an 8 versus having to spike down. I was wondering if such an emergency descent could be done without a Figure 8 by using some kind of knot combination.
As I mentioned, I tried a Klemheist hitch on a doubled rope and it worked pretty well for a short descent. I stopped descending when I let go and was able to start descending again by applying pressure to the top wrap of the hitch. I'll need to try it on a longer descent to see if it continues to perform well. The cord got pretty hot on the short descent.
OTG BOSTON
Addicted to ArboristSite
I was always told that the Kleimheist was not suitable for decending. It seems as though the friction you experienced prooves it.
I was in a huge Oak tree at a Mass. Arborists Arborday event the first year I started climbing. An old timer asked if I needed help (it was pretty obvious I wasn't making it down in time for lunch). He had me place a line for him and footlocked with a traditional two wrap prussic made from 1/2 line. Pruned his way up and around, and descended the same way.
In my limited comp. experience we footlocked(timed footlock event) up with either a three wrap prussic or a kleimheist (no mechanical ascenders) and descended on a fig 8. I have to believe if it were O.K. to descend on the prussic they would have asked us to, to speed up the event.
I was in a huge Oak tree at a Mass. Arborists Arborday event the first year I started climbing. An old timer asked if I needed help (it was pretty obvious I wasn't making it down in time for lunch). He had me place a line for him and footlocked with a traditional two wrap prussic made from 1/2 line. Pruned his way up and around, and descended the same way.
In my limited comp. experience we footlocked(timed footlock event) up with either a three wrap prussic or a kleimheist (no mechanical ascenders) and descended on a fig 8. I have to believe if it were O.K. to descend on the prussic they would have asked us to, to speed up the event.
Tree Machine
Addicted to ArboristSite
This would require the person on the ground to untie your base anchor, and then you haul one end of the rope up and tie and set the hitch. This will work, but takes two persons and a lot of extra motion for this one-person task that can be simplified quite a bit.rmihalek said:
What are you using for ascent, Mihalek? In having asked about descending a doubled line, I assume you're ascending, 1:1 up a doubled line and that pretty much means dual ascenders. Is this right?
Ascending 1:1 up a doubled line as compared to ascending 1:1 up a single line is really very similar.
SRT gets more elasticity/bounce from the line; than DdRT. DRT gives less elasticity/ bounce to fight when walking up the line, like DdRT. i imagine someone can get to the beat right to use the bounce to throw into next lift; but not me, so the elasticity totally works against me, adding distance to climb etc.
Without Base Anchor; i can SRT up to TIP, secure with lanyard and untie running Bowline, retie in for DdRT. Alternatively have rigging line or other line krab-bed to Running Bowline of lifeline higher than you will need to climb. Do a few cuts on way up, secure self with lanyard (sometimes with a sling too, even if sling support is not totally support worthy, bug just stabilizing or more comfy to lean against etc.), and use rigging line to remotely pull Running Bowline open and bring to you. Retie in for DdRT around that same support; and have rigging line too. Without caring it up, ready to usewith load or have stuff pulled back up .
i like Pantin and can feel slip of the line when just stepping on one side with it in DRT.
Without Base Anchor; i can SRT up to TIP, secure with lanyard and untie running Bowline, retie in for DdRT. Alternatively have rigging line or other line krab-bed to Running Bowline of lifeline higher than you will need to climb. Do a few cuts on way up, secure self with lanyard (sometimes with a sling too, even if sling support is not totally support worthy, bug just stabilizing or more comfy to lean against etc.), and use rigging line to remotely pull Running Bowline open and bring to you. Retie in for DdRT around that same support; and have rigging line too. Without caring it up, ready to usewith load or have stuff pulled back up .
i like Pantin and can feel slip of the line when just stepping on one side with it in DRT.
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PUclimber
ArboristSite Operative
You don't have to have someone untie your rope going up single line. You can tie a running bowline if you isolate the limb but you have to go all the way up to that tie in point to untie to get switch over to your drt. This is an okay practice or you can tie off to the base climb up the tree with an extra line and then run drt off a pulley or something attached to a friction hitch where you can work the tree all the way down and then untie from the base of the tree and drop all your equipment out of the tree. This is also helpful in case of an emergency where you have no one else that can climb if you use a belay device or a friction device such as a portawrap then you can be lowered from the ground if you have enough rope on the other end.Tree Machine said:
Tree Machine
Addicted to ArboristSite
Agreed. I used to favor 13mm stable braid for years, because the bounce was nil. Then the 11 mm stuff came on the market, Velocity being relatively low stretch. MK3, a 11 mm static line is sweet in overcoming rope bounce. Stable braid, I've learned since then, can be special ordered in 11 mm. Very nice.TheTreeSpyder said:
Nice nugget there, Spidey. That's a good one.TheTreeSpyder said:
PUclimber said:
I'm doing all climbing with DdRT for now. I was experimenting with friction hitches using a doubled rope through a false crotch that I made with webbing slings and a carabiner. I will probably eventually purchase a figure 8 and a steel ring friction saver to make a false crotch with but wanted to see if I could get something to work with the gear I already had.
SuperDIYer
ArboristSite Lurker
Hey Tree Machine - Cross Loaded Biener?
Pardon me for being picky here, but the biner anchoring your Gri-Gri looks cross-loaded (slightly) by the large leather ends on your sling. I see that its a locking biener, but is this a concern at all?
Thanks
jtz
Pardon me for being picky here, but the biner anchoring your Gri-Gri looks cross-loaded (slightly) by the large leather ends on your sling. I see that its a locking biener, but is this a concern at all?
Thanks
jtz
PUclimber
ArboristSite Operative
TM,
That was the set up I was talking about as far as accessing the canopy but you can back up the ascender with a vt on top of that run a carabiner through the eyes and through the hole in the top of your ascender and have a pulley running off that carabiner with your drt system running off the pulley so you can work the tree drt after you get to your canopy or tie in point. So this way you've got a floating anchor point in the tree on your rope. You have to back it up though by tying a slip not below your ascender and clipping a carabiner though the slip not.
That was the set up I was talking about as far as accessing the canopy but you can back up the ascender with a vt on top of that run a carabiner through the eyes and through the hole in the top of your ascender and have a pulley running off that carabiner with your drt system running off the pulley so you can work the tree drt after you get to your canopy or tie in point. So this way you've got a floating anchor point in the tree on your rope. You have to back it up though by tying a slip not below your ascender and clipping a carabiner though the slip not.
Tree Machine
Addicted to ArboristSite
That's a good eye, Super. I suppose I should have snugged the one eye over the other eye and dressed it a little better. Still, crossloading needs to be looked at from the standpoint of forces, and where those forces are on the biner. With those eyes, they are distributing, or spreading out the load across the top of the caribiner (it was positioned upside down). The forces are still vertical, the caribiner being pulled lengthwise, parallel to the spine. Crossloading, or sideloading as it sometimes referred, is when forces are applied perpendicular to the axis of the spine.SuperDIYer said:
Anyway, the magnitude of force on the biner is approximately equal to my weight, 165 lbs or 0.73 Kn. This is a 50 Kn triple lock, hardly worrisome. The focus, when setting this rig, was to make sure the eyes didn't interfere with the gate.
I looked up 'crossloading' in the ISA glossary of arboricultural terms and it's not in there. It was a good question, Super, off the subject, but so was the picture. Normally I anchor using the rope, no slings, and sink two biners, positioned opposite and gates opposed where one of the biners is a triple locker. This particular day I was trying out a brand new 200 foot MK-3 and had a ground guy so I set up a rescue rig. That was also the only time I've ever used that giant blue strap.
